As a 14-year-old, she picked up a spade and joined the rest of wartime Britain in the Dig for Victory campaign. Seven decades later, though no longer wielding the spade herself, the Queen, now 83, has again embraced the "grow your own" movement.

For the first time since the war, fruit and vegetables are to be found in an allotment-sized plot in the gardens of Buckingham Palace.

The yield will not be sufficient to wholly sustain the British royal family and palace staff, and a 16ha back garden negates the inconvenience of allotment waiting list times of up to 40 years in some London boroughs.

But from now on token quantities of fresh tomatoes, beans, onions, leeks, carrots and other homegrown produce will be transported to the palace kitchen.

The first harvest - a selection of Cambridge Favourite strawberries - was served to the Queen and Prince Philip, on his 88th birthday last week.

She is not the first head of state to highlight frugality in these tough times. US President Barack Obama put his wife in charge of a White House herb and vege patch, though the Queen's plans are said to have been devised much earlier.

Buckingham Palace's 4m by 10m plot is in a challenging, north-facing area to the garden's rear, tight up against the Gardeners' Yard. "Not ideal, but it is the only open space available, because everything is so landscaped," admitted deputy gardens manager Claire Midgley, 32, one of eight gardeners at the palace.

It was her ambition to reintroduce vegetables. "The Queen is always interested in looking at new ideas for the garden. Her Majesty approved of the suggestion to plant an experimental allotment," said a spokeswoman.

Part-shaded by a 100-year-old mulberry bush, a scionwood from one of Shakespeare's trees, the plot is protected from mammals by the palace's high walls and electric fencing. Challenging Prince Charles in the eco-stakes, chemicals have been banned.

In 1918, as part of Queen Mary's wartime austerity drive, the 175m-long herbaceous border was ripped out and planted with "an abundance of royal turnips".

During World War II the same border was again usefully employed, though for a more varied crop, as food rationing gripped Britain and encouraged George VI to enforce the Government's message and coax yield from every available patch of earth.